Do any of you know of a small (read this as short) fiber link I can use
on a long CAT-5E line to isolate two buildings' routers/hubs from ground-
potential variations that might cause wire-connected equipment to fail?
My idea is to run Cat-5 for the long line, then insert a Cat-5 to fiber
to Cat-5 link somewhere in the line as the electrical equivalent of a
"thermal break". My reasoning is that I already have the copper, and
fiber over 500' would be quite expensive. Correct me if I'm wrong.
I live in a lightning zone, and the two buildings are on different
transformers, so the potential differences could be large.
John Navas fired this volley in
Thanks. I've used Transtector plug-in protectors with good success.
I was looking for something more in the line of "non-sacrificial"
The cheapest multi-mode pre-terminated fiber I can find (with a pulling
eye) is about $500 for a 400-foot run. Then two media-converters add
another $150, or so.
I was hoping there was a "link in a box" arrangement for this very
John, have you used the Transtectors for this purpose? If so, how do
they hold up to nearby cloud-to-ground or cloud-to-powerline strikes?
They make media converters. They're CAT5 10/100 on one end and fiber on the
other. You can span up to 1km with them. Allied Telesyn made some decent
low-end ones. Check eBay for them. Then you'll need the fiber cabling, and
have it terminated with the appropriate ends for your media converts (often
either ST or SC connections). When you pull (or bury) the fiber consider
getting a bundle with more than just one pair. If a fiber should break
you'd want a spare in there. I'd pull at least a 4 strand.
"Bill Kearney" fired this volley in
Yes, that's the other viable option. I haven't gleaned Ebay yet for
supplies, but if I buy new 62.5/125um 4-strand cable with SC connectors
and a pull ring, it'll cost over $500 for just the cable to go 400 feet.
It's more of a mental block, I guess, than anything else. I was hoping
for a solution in a box, but when I look at rigging it up myself, then
suddenly I cannot see the advantage of just running a short optical
jumper -- I seem to lean to making the whole link out of fiber, and doing
away with the copper entirely.
Oh, well... I do NOT want to have to replace the components every time we
get a strike on the lines down our road. We pretty much have had to do
that in the past (when on dial-up). Just like the high-speed link will
be, our phones are common to both buildings, even though the power is on
separate transformers; and every time one building took a hit, both ends
So I suppose I'll suck it up and go the optical/media converter route.
(yet another $700 out of the construction budget)
John Navas fired this volley in
That, I can do. I installed medical business-management systems for 22
years here in Florida. The considerations for _guaranteed_ thrice-annual
strikes on incoming service are costly, but do-able.
lightning protection is not just about the convertor....
note every convertor i have seen uses a power feed, so your isolation scheme
has a couple of holes in it - a strike at either end will cause a spike on
the ground voltage as the strike dissipates to earth.
i have also had RS422 equipment with part of the card vaporised rather than
just not working when there was a strike on a road - our expensive shielded
cable ran a couple of meters away and 1 m down........
golden rule for telecomms is that the expensive bit is digging the hole -
put down multiple tubes so you have some future options (rule of thumb used
to be £100 / m for public roads - on a private site things should be
and since the fibre is inherently safe you can run a power cable down
another tube in the same hole in the ground (or even the same one, but big
cables tend to break small cables in the same duct when you pull them in)
First, routine to have direct strikes and no damage. Your telco
connects its $multi-million computer to buildings, via overhead wires,
all over town. Every thunderstorm typically creates maybe 100 surges
- without damage. If every wire is earthed where entering the
building, then lightning need not seek earth ground, destructively,
via interior electronics.
Same solution was installed in FL's Orange County Emergency Response
facilities. Protectors and isolation were not a solution:
A first building may act as a lightning rod to find earth ground,
destructively, via electronics in the second building. Solution was
discussed recently. This problem and a simple, inexpensive solution
that was standard even 100 years ago is in "Long cat5 run question" in
alt.internet.wireless on 24 Jan 2008 at:
Second, any protector destroyed by a surge was not providing
protection. But failure (by being grossly undersized) gets myths to
promote those effective and grossly overpriced solutions. The
standard protection system means a direct lightning strike and
resulting surge is not even known. Properly earthed protection is that
routine and effective that nobody knows when it happens. Earthing
defines quality of any surge protection 'system'; including essential
short (low impedance) connections from each wire to a single point
Third, a least expensive solution is also most effective. Only one
component is always required in every surge protection system: earth
ground. That requirement applies to every incoming wire - not just a
Cat5 cable. Damage is created when a surge is permitted inside the
building - permitted to find earth ground, destructively, inside that
building. One path might be incoming on AC electric and outgoing to
earth via that Cat 5 wire. Do not assume damage on a Cat 5 cable is
due to a surge entering on Cat 5 wires. A surge could also be
incoming on AC mains and outgoing to earth ground, destructively, via
Cat 5 wires.
"stephen" fired this volley in
Yes, thanks. I've got lots of experience "protecting" computers from
lightning. I made a living doing (in part) that very thing for 22 years.
And thus, the optical "break". Each media converter would get its power
from its end of the link -- by the very means you suggest below.
That might normally be, but I can have the trench for $125. There will
be several pipes in the hole for convenience's sake.
Not if they're properly harnessed and lubricated, and the fill-factor is
w_tom fired this volley in news:3a77abfd-3756-4375-8418-
That was awfully didactic, but hardly accurate. As an example, we're in
one of the "old copper" districts. Nothing is less than 15 years old.
And Nothing (I mean zip, zero, nada, zilch) runs in the air. There isn't
a telco pair on a pole within ten miles of here. It's ALL underground,
for the obvious reasons.
Every wire? Surely you mean "every cable". What happens to your re-
transmission rate when every wire is grounded?
Now, if instead you meant spark-gap protection -- why sure. I'm an old
amateur radio guy, and have a wealth of experience setting up big dipoles
and inverted-vee antennae, then leading the feedline into my house.
That would be pretty dangerous without a simple "cannot fail" system like
a spark-gap arrestor.
(Hint... put your arrestor where you can visually inspect it frequently.
Don't ask how I know )
Makes no difference whether wires are overhead or underground. Same
problem needs the same solution. A professional's applicaiton note
demonstrates even underground wires must have the 'less than 10 foot'
connection to earth ground:
Quality of earthing determines effectiveness of that protector
(spark gap or devices specially made for your ethernet wire).
Earthing, the length of that earting connection, and whether every
other wire also connects short to that same earthing electrode
determines whether damage can happen. That is the point in both
Electrical Engineering Times articles and these others that apply to
Accurately stated: every wire in every cable, even in the telco's
CO, gets connected to earth ground. Please reread those posts with
care. That spark gap 'grounds' the antenna wire. Clearly noted is
that grounding is make by hardware (ie coax cable) or via a
protector. That is what a protector does - make that grounding
connection. Aagin, read both front page EE Times articles for further
Some examples to connect each ethernet wire to earth ground
(equivalent to spark gaps):
Similar thread. While you are at it, read the replies.
If using a protector, such as Transtector, at the entrance to each
building, the ground connection should connect with a *short* wire to
the earthing wire at the power service (not just an earthing electrode).
An example of a long connection is in an IEEE guide on surges and surge
pdf page 40. A long connection allows a large voltage between
signal and power wires which shows up at computers connected to both.
The NIST guru on surges, has written "the impedance of the grounding
system to `true earth' is far less important than the integrity of the
bonding of the various parts of the grounding system."
And contrary to w_?s beliefs, plug-in suppressors can be effective, as
the IEEE guide shows. Plug-in suppressors work primarily by clamping the
voltage on all wires (power and signal) to the common ground at the
suppressor, not earthing. Note that power and signal (phone, Cat-5, ...)
all have to go through the suppressor.
The problem with a link-in-a-box fiber optic isolator is that the Cat-5
converters on each side of the fiber need to be powered from the
different buildings. Otherwise, if both of the converters are powered in
building ?A? and a Cat-5 goes to building ?B? you have the same high
voltage problem between buildings (unless the unit has very high voltage
isolation between power and signal on one side.)
bud-- fired this volley in
Exactly, and as I indicated in an earlier post.
Despite w's assertion to the otherwise, I have a more than just a bit of
experience with this art. His failing to discriminate between true
grounding and providing a low-impedance avalanche path to ground was what
He preaches loudly, but misses the simplest things.
Where did I say that? A low impedance path to ground is essential
to protection. Earthing provides the protection. Also provides were
sources that say same. Even Bud's 'post and paste' reply says the
protectors he promotes do not provide that protection because the
essential connection to earth ground is not provided.
The question was protecting ethernet ports from damage due to a
connection between buildings. Provided was how that protection has
been installed routinely for 100 years without the expense of fiber
optics. If I, all telcos, broadcast stations, military facilities,
etc do same as you are saying, then why/where the confusion?
If you have a surge that produces only 1000A to earth and a rather low
10 ohms impedance to earth, the ground reference at the building will be
raised 10,000V above ?absolute earth potential?. Keeping the ?ground?
references for power, ethernet, phone, ... at the same relative
potential is more important than the impedance to ground. That requires
a *short* connection from signal entrance protectors to the earthing
wire at the power service. (In US services, the neutral is bonded to
?ground? at the service - the power system ?ground? reference).
Repeating - the NIST guru on surges, has written "the impedance of the
grounding system to `true earth' is far less important than the
integrity of the bonding of the various parts of the grounding system."
If the only grounding electrode is a ground rod, generally 70% of the
voltage drop away from the rod is in the first 3 feet. The voltage from
?ground? references in the building to the earth over 3 feet from the
rod will be at least 7,000V.
If the entrance protector for ethernet wires is not near the power
service, the voltage between ethernet and power wires can not reliably
be kept low enough. The IEEE guide says a 10 ft ?ground? wire from phone
entry protector to the common point is too long. The guide has an
illustration of a 30 ft ?ground? wire from a cable entry block
permitting 10,000V between cable and power wiring (pdf page 40).
w_ has a religious belief (immune from challenge) that surge protection
must use earthing. Thus in his view plug-in suppressors (which are not
well earthed) can not possibly work. The IEEE guide explains plug-in
suppressors work by CLAMPING the voltage on all wires (signal and power)
to the common ground at the suppressor. Plug-in suppressors do not work
primarily by earthing. The guide explains earthing occurs elsewhere.
(pdf page 40.)
Another guide on surges and protection, from the NIST
says plug-in suppressors are effective.
w_?s cut and paste assertions ignore (and twist) what the IEEE and NIST
guides say because the guides challenge w_?s religious belief in earthing.
And I do not promote any protection method - I only promote accurate
information as opposed to w_?s misinformation. Read the authoritative
sources - the IEEE and NIST guides.
Then read w_?s sources that say plug-in suppressors are NOT effective -
oops, there aren?t any.
That NIST guide says only earthing makes a protector effective.
Every responsible source says same. Bud is promoting protectors that
have no earthing. He 'cut and pastes' half truths hoping you ignore
engineering facts. Even both front page Electrical Engineering Times
articles bluntly define earthing as essential to protection. That
NIST citation says same on page 6 (Adobe page 8):
Bud says earthing is not critical and essential. Profits are at
risk if you learn what an effective protector does and what plug-in
protectors cannot do. Ask Bud for a spec sheet from any plug-in
manufacturer that claims protection. He cannot. That missing fact
says defined an ineffective protector. A protector without earthing
does not even claim to provide protection. It has Bud to promote
NIST repeats what is essential on page 17:
What happens when earthing is missing or improperly installed? A
Bud citation demonstrates damage because a protector is 1) too far
from earth ground and 2) too close to appliances. Page 42 Figure 8
protector without earthing (as defined by both front page EE Times
articles), means the protector earths a surge, 8000 volts
destructively, through an adjacent TV. Just another source that
demonstrates why proper earthing is essential for surge protection. A
protector without that short connection to earth ground even creates
appliance damage - 8000 volts destructively through the TV. Page 42
Figure 8 is blunt. Bud must obfuscate this reality. Effective
protection earths every incoming wire where that cable enters the
This concept was understood even 100 years ago. Principle is
stated bluntly by the IEEE where IEEE makes recommendations. IEEE Std
141 - The Red Book states:
That same concept is required in all communication circuits as
defined by the telco industry Telcordia standards. Protection is
always about earthing every wire where the cable enters a building.
No earth ground means no effective protection.
Lloyd will connect two buildings. No fiber optic required today as
was not needed 50 years ago. Routine is to connect buildings with no
surge damage. But only if the incoming cable is properly earthed.
Protectors that can make that earthing were posted earlier.
Qwest standards demand properly earthed protectors IF that cable
exceeds 50 feet. If that interconnection is shorter and if both
buildings don't share the same single point earth ground, then
earthing at both ends is still recommended. Those who want even
better protection would interconnect those two building earth grounds
with a bare and buried ground wire. More reasons why fiber optic
isolators are not needed.
A protector is only as effective as its earth ground. A protector
without that short and dedicated earthing connection may even earth
surges, destructively, through household appliances. Page 42 Figure
8. Should surge damage occur, then ham radio operators, 911
Emergency response facilities, commercial broadcast stations, military
facilities, cell phone towers, telco COs (switching centers), etc
locate faults in the earthing system. Professionals did same in
Nebraska. Damage created, in part, because operators compromised
earthing due to ignorance also promoted by Bud:
"Proper Copper Grounding Systems Stops Lightning Damage at Nebraska
FM Station" discusses another essential earthing inspection /
correction. This post discusses secondary protection. Primary
protection is defined by utility earthing (power poles, underground
transformers, etc). What also makes primary protection effective? An
All electronics contain effective protection. Internal protection
that is overwhelmed if incoming wires are not properly earthed.
Internal protection also compromised by a protector too far from earth
ground and too close to electronics - Page 42 Figure 8. Only
component always required in every surge protection system: each
building needs a single point earth ground. Any solution without
earthing can create surge damage as demonstrated in Nebraska and on
Page 42 Figure 8. Bud fears you might learn this. Profits would be
at risk. A routine solution that makes expensive fiber optics
If Bud's protectors provided effective protection, then manufacturer
specs would make that claim. Bud was asked maybe 300 times to provide
those specs. He never does. He cannot provide what never exists. Bud
is promoting myths.
Both the NIST and IEEE guides say plug-in suppressors are effective.
I am promoting only accurate information against w_?s religious beliefs.
I hope you read reliable sources. I suggest the IEEE and NIST guides
instead of w_?s cut and paste dogma.
What does the NIST guide really say about plug-in suppressors?
They are "the easiest solution".
Poor w_ can?t understand me, or the IEEE guide, or the NIST guide
because his religious belief in earthing is challenged . Regarding
plug-in suppressors, the IEEE guide says earthing occurs elsewhere. Both
the IEEE and NIST guides say earthing is important.
The illustration shows damage because a cable entry protector is 30 feet
from the power system and surge current on the ?ground? wire from cable
entry to power service produces 10,000V between cable and power wires. A
lot of cable and phone installations have entry protectors distant from
the power service.
The illustration has nothing to do with ?too close to appliances?.
The illustration has a surge coming in on the cable service. There are 2
TVs, one is connected to a plug-in suppressor. The plug-in suppressor
protects TV1, connected to it.
Without the plug-in suppressor at TV1 the surge voltage at TV2 is
10,000V. With the suppressor the voltage at TV2 is 8,000V. It is simply
a *lie* that the plug-in suppressor at TV1 in any way contributes to the
damage at TV2.
The point of the illustration for the IEEE, and anyone who can think, is
"to protect TV2, a second multiport protector located at TV2 is required."
w_ says suppressors must only be at the power service. In this example a
service panel protector would provide absolutely *NO* protection. The
problem is the cable entry ?ground? wire is too long. The IEEE guide
says in that case "the only effective way of protecting the equipment is
to use a multiport [plug-in] protector."
Because plug-in suppressors violate w_'s religious belief in earthing
he has to twist what the IEEE guide says about them.
The IEEE Emerald book ("IEEE Recommended Practice for Powering and
Grounding Sensitive Electronic Equipment"), an IEEE standard, recognizes
plug-in suppressors as an effective protection device. This is the most
appropriate IEEE standard for protecting electronics.
The IEEE guide was peer reviewed within the IEEE and represents the
views of the IEEE (pdf page 4).
The statement of religious belief in earthing #1. The IEEE guide says
plug-in suppressors work primarily by clamping the voltage on all wires
to the common ground at the suppressor, not earthing.
I have agreed that protectors where the cable enters the building are a
good idea. But the protectors will not have maximum effectiveness unless
the entry protector is connected with a *short* ?ground? wire to the
earthing wire at the power service. The cable entry ground block in the
IEEE illustration above was connected with a 30 ft ?ground? wire and
10,000V developed between power and cable wires.
Statement of religious belief in earthing #2.
Everyone is in favor of earthing. The question is whether plug-in
suppressors work. Both the IEEE and NIST guides say plug-in suppressors
are effective. Read the sources.
There are 98,615,938 other web sites, including 13,843,032 by lunatics,
and w_ can't find another lunatic that says plug-in suppressors are NOT
effective. All you have is w_'s opinions based on his religious belief
w_ has never answered simple questions:
- Why do the only 2 examples of protection in the IEEE guide use plug-in
- Why does the NIST guide says plug-in suppressors are "the easiest
- How would a service panel suppressor provide any protection in the
IEEE example, pdf page 42?
- Why does the IEEE Emerald book include plug-in suppressors as an
effective surge protection device.
Bizarre claim - plug-in surge suppressors don't work
Never any sources that say plug-in suppressors are NOT effective.
Twists opposing sources to say the opposite of what they really say.
Invents opinions and attributes them to opponents.
Attempts to discredit opponents.
w_ is a purveyor of junk science.